An aluminium weld-in bung giving a male AN8 flare port. Stepping up to AN8 buys you meaningfully more flow than AN6, which is why it is the usual choice for main fuel feed on forced-induction and higher-output engines, oil cooler lines, turbo drains and surge tank inlets and outlets. Aluminium construction means it is designed to be TIG welded into alloy fabrications such as billet or sheet surge tanks, header tanks, catch cans and aluminium sumps. Tack it in opposing points and allow it to cool between passes so the larger port does not pull out of round. Sealing is on the 37-degree flare, so no thread sealant.